linux-kernel - Re: [PATCH v2] KVM: x86: check PIR even for vCPUs with disabled APICv

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Message-ID: <YZZ8hAjbIJnkkraD@google.com>
Date:   Thu, 18 Nov 2021 16:17:08 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Maxim Levitsky <mlevitsk@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] KVM: x86: check PIR even for vCPUs with disabled APICv

On Thu, Nov 18, 2021, Paolo Bonzini wrote:
> On 11/18/21 10:56, Maxim Levitsky wrote:
> > vmx_sync_pir_to_irr has 'if (KVM_BUG_ON(!vcpu->arch.apicv_active,
> > vcpu->kvm))' That has to be removed I think for this to work.
> 
> Good point.

Hmm, I think I'd prefer to keep it as

	if (KVM_BUG_ON(!enable_apicv))
		return -EIO;

since calling it directly or failing to nullify vmx_x86_ops.sync_pir_to_irr when
APICv is unsupported would lead to all sorts of errors.  It's not a strong
preference though.